View Full Version : speed control of dc motor( for line-following robot)

03-23-2005, 11:14 PM
i tried to control the speed of the line-following-robot (at the turnings)using pulse width modulation. but it did'nt work out well. actually, i am planning in such a way that the speed of the robot should decrease continuously from a certain distance b4 the turn ( for eg. it should keep on decreasing speed from 10 cm away from the turn) .can anybody suggest an idea for the speed control and the prediction of the turn ?????

03-24-2005, 06:42 PM
You need to have an onboard vision system ... a webcam perhaps ... with some image processing support...that's the way you can predict the turn...but these systems may turn out to be a little too complex having onboard signal processing capabilities.

Other option is drive the bot from a PC. And have an overhead camera for input ...

03-26-2005, 06:38 PM
the simple way is to mark on the line before a turn which can be sensed by the robot, that a turn is approching or a vision sensor. otherwise u have to reduce the normal speed of the robot so that during turns also it can maintain stability.

03-26-2005, 10:58 PM
Try extending your sensor board out front and at a 10 ~ 15* angle from the ground (effectively sensing a few cm in front of the board). For one of my line followers, the sensor board had to be 4 cm off the ground. I used special powerful IR leds. You might need to use more power leds if you want to sense further ahead. But your programing will have to take of the lag between your sensing and where your body actully is.